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| author | Peter Hurley <peter@hurleysoftware.com> | 2014-11-05 12:13:02 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-05 18:50:42 -0800 |
| commit | 2febdb632bb96235b94b8fccaf882a78f8f4b2bb (patch) | |
| tree | f4740b43b225a863f05df7edb59d3b3badfdb445 | |
| parent | 2aff5e2bc62db43e05c814461a08aff0fc2b7fe5 (diff) | |
| download | linux-2febdb632bb96235b94b8fccaf882a78f8f4b2bb.tar.gz linux-2febdb632bb96235b94b8fccaf882a78f8f4b2bb.tar.bz2 linux-2febdb632bb96235b94b8fccaf882a78f8f4b2bb.zip | |
tty: Preset lock subclass for nested tty locks
Eliminate the requirement of specifying the tty lock nesting at
lock time; instead, set the lock subclass for slave ptys at pty
install (normal ttys and master ptys use subclass 0).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/pty.c | 2 | ||||
| -rw-r--r-- | drivers/tty/tty_mutex.c | 19 | ||||
| -rw-r--r-- | include/linux/tty.h | 1 |
3 files changed, 12 insertions, 10 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index bdb8fd1a2026..11db7dc8676b 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -399,6 +399,8 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty, if (!o_tty) goto err_put_module; + tty_set_lock_subclass(o_tty); + if (legacy) { /* We always use new tty termios data so we can do this the easy way .. */ diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c index f43e995c7a0f..4486741190c4 100644 --- a/drivers/tty/tty_mutex.c +++ b/drivers/tty/tty_mutex.c @@ -13,15 +13,14 @@ enum { TTY_MUTEX_NORMAL, - TTY_MUTEX_NESTED, + TTY_MUTEX_SLAVE, }; /* * Getting the big tty mutex. */ -static void __lockfunc tty_lock_nested(struct tty_struct *tty, - unsigned int subclass) +void __lockfunc tty_lock(struct tty_struct *tty) { if (tty->magic != TTY_MAGIC) { pr_err("L Bad %p\n", tty); @@ -29,12 +28,7 @@ static void __lockfunc tty_lock_nested(struct tty_struct *tty, return; } tty_kref_get(tty); - mutex_lock_nested(&tty->legacy_mutex, subclass); -} - -void __lockfunc tty_lock(struct tty_struct *tty) -{ - return tty_lock_nested(tty, TTY_MUTEX_NORMAL); + mutex_lock(&tty->legacy_mutex); } EXPORT_SYMBOL(tty_lock); @@ -56,7 +50,7 @@ void __lockfunc tty_lock_slave(struct tty_struct *tty) WARN_ON(!mutex_is_locked(&tty->link->legacy_mutex) || !tty->driver->type == TTY_DRIVER_TYPE_PTY || !tty->driver->type == PTY_TYPE_SLAVE); - tty_lock_nested(tty, TTY_MUTEX_NESTED); + tty_lock(tty); } } @@ -65,3 +59,8 @@ void __lockfunc tty_unlock_slave(struct tty_struct *tty) if (tty && tty != tty->link) tty_unlock(tty); } + +void tty_set_lock_subclass(struct tty_struct *tty) +{ + lockdep_set_subclass(&tty->legacy_mutex, TTY_MUTEX_SLAVE); +} diff --git a/include/linux/tty.h b/include/linux/tty.h index a07b4b415db8..196c352a5ce8 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -640,6 +640,7 @@ extern void __lockfunc tty_lock(struct tty_struct *tty); extern void __lockfunc tty_unlock(struct tty_struct *tty); extern void __lockfunc tty_lock_slave(struct tty_struct *tty); extern void __lockfunc tty_unlock_slave(struct tty_struct *tty); +extern void tty_set_lock_subclass(struct tty_struct *tty); /* * this shall be called only from where BTM is held (like close) * |